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Nest-site biology of the California condor

Condor

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Abstract

A study of 72 historical and recent nests of the California Condor (Gymnogyps californianus) has revealed considerable variability in nest-site characteristics. This paper primarily summarizes the data on nest elevations and dimensions, entrance orientations, nest longevity and re-use, vulnerability of sites to natural enemies, and use of sites by other species. Although all known nests have been natural cavities, some have been little more than overhung ledges on cliffs, while others have been deep, dark caves with nest chambers completely concealed from the outside. Two sites have been cavities in giant sequoias (Sequoiadendron giganteum). Contrary to previous assumptions, condors do modify the characteristics of their nest sites significantly and commonly construct substrates of coarse gravel on which to rest their eggs. Many nests have been completely accessible to terrestrial predators, many have been poorly protected from avian predators, and some have had structural flaws leading directly to nesting failure. The use of suboptimal sites has not been clearly related to a scarcity of better quality sites.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
Nest-site biology of the California condor
Series title:
Condor
Volume
88
Issue:
2
Year Published:
1986
Language:
English
Contributing office(s):
Patuxent Wildlife Research Center
Description:
228-241
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Condor
First page:
228
Last page:
241
Number of Pages:
14